Acoustic Habitat
Degradation assessment tool
The shipping noise is the single ubiquitous source of noise in the ocean that has far and wide impact in the ocean. The low frequency shipping noise has minimalattenuation during propagation in the undersea medium, thus has maximum impact across the entire ocean region due to the distributed nature of shipping traffic. The direct linkage of shipping traffic with the global economic index makes it extremely difficult to motivate the political leadership to contain or regulate the shipping traffic. The low frequency ambient noise due to shipping has been documented to have doubled (3 dB) every decade since 1950. Thus, there is a case for bringing more transparency in the management to encourage stakeholder participation.
Low frequency ambient noise below 1 kHz is known to be dominated by distantshipping and the shipping traffic has a unique and evolving temporal andspatial pattern. The Automatic Identification System (AIS) used by Vessel Traffic Services (VTS) is a unique system that monitors the movement of all voyaging ships above 300 Gross Tonnage (GT) and passenger ships regardless of size. The AIS data provides complete description of the ship and its voyage details. Radiated noise from a marine platform is a function of its type and the underwater noise propagation properties at any given location. Utilizing the AIS data, it is possible to quantify the Underwater Radiated Noise(URN) in a specific area.
The low frequency ambient noise overlaps with the hearing of marine mammals particularly the big whales and the level of degradation is severe, as manifested in the frequent stranding of big whales across the globe. Marine mammals are known to use sound for multiple biologically critical functions like navigation, communication, foraging, finding mates for breeding, avoiding predators and more. The increasing noise in the ocean masks their ability to perceive the environment around them and results in habitat degradation. We refer this as Acoustic Habitat Degradation.
- Real-time spatio temporal assessment of the acoustic habitat degradation in the IOR.
- Species specific vulnerability assessment with real-time correlation with the site specific acoustic habitat degradation.
- Continuous availability of data for realistic cause & effective assessment.
- Complete technology driven tool to avoid any biases.
- Effective Marine Spatial Planning based on realistic site specific inputs.
- Availability of short termand long term ground data for effective policy formulation.
- High level of transparency for enhanced stakeholder confidence and participation.
- Real-time spatio temporal assessment of the acoustic habitat degradation in the IOR.
- Species specific vulnerability assessment with real-time correlation with the site specific acoustic habitat degradation.
- Continuous availability of data for realistic cause & effective assessment.
- Complete technology driven tool to avoid any biases.
- Effective Marine Spatial Planning based on realistic site specific inputs.
- Availability of short termand long term ground data for effective policy formulation.
- High level of transparency for enhanced stakeholder confidence and participation.
The assessment tool has two components related to the source and the receiver. The shipping noise being the source has a spatio-temporal characteristics that needs to be assessed to manage the acoustic habitat degradation effectively. The source characteristics need to be matched with the receiver (the marine species), to assess the vulnerability of the specific species. The proposed tool will provide a comprehensive source-path-receiver model to facilitate a real-time assessment of the acoustic habitat degradation. The underwater medium (referred as path) particularly in the tropical littoral waters of the Indian Ocean Region (IOR), present random fluctuations thereby modifying the source prior to reaching the receiver. The path related modifications have been accounted for in the proposed tool.


The real-time presentation of the low frequency ambient noise due to shipping is a critical step in the assessment of the acoustic habitat degradation at any location. The shipping noise being the dominant component of the low frequency ambient noise provides the realistic assessment. The intensity of noise at any location, determines the level of degradation, at times leading to fatalities. The real-time and continuous availability of data can facilitate multiple analysis that can aid the effective management of the source.
The high intensity levels will have unique impact for multiple species. Each species has its own sensitivity to the exposure and thus needs to be assessed,prior to proposing any containment strategy. The vulnerability assessment has to be species specific and based on the population abundance, the urgency of the conservation measures and strategies need to be formalized. The real-time and continuous availability of the species specific acoustic habitat degradation inputs will facilitate effective conservation measures.
Real-time Assessment of the Degradation
The realistic awareness of the extent of degradation will allow planning for future activities. Marine Spatial planning for achieving Sustainable Development Goals (SDGs) can be effectively undertaken based on such inputs. It will allow a more scientific approach to ensuring sustainable growth model.
Real-time Cause & Effect Assessment
The cause & effect assessment is the most critical aspect for any effective management initiative. The continuous availability of such micro data will facilitate very detailed study to establish the cause & effect taking into account diverse aspects. The specific design and operations related aspects can be investigated for their contribution to the overall URN.
Policy Formulation
The short term and long term policy formulation based on scientific data is the dream for any decision maker. This tool will allow nuanced approach that will bring down the binary of DevelopmentVs Environment. Even import of technologies and in many cases, even policy frameworks can be avoided based on such realistic local inputs. It will allow harmony among the policy makers and the stakeholders with higher levels of transparency.
Long Term Research Inputs
Sustainable growth has multiple facets and realistic understanding of the ground realities is a very critical aspect.Such inputs can go a long way in facilitating effective governance. The Underwater Domain Awareness (UDA) facilitated by such a tool in the long term will allow stakeholder integration and seamless interactions. The pooling of resources and synergising of efforts across stakeholders will encourage optimum resource utilization.
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